Spikefrequency adaptation is a prominent property of neuronal dynamics in neural information processing. The external electric field has effect on the generation and conduction of neural information, and the dynamic behaviors of the neural system. Based on the leaky integrateandfire (LIF) model, a modified LIF model under the external electric field is established. From the membrane potential curve and the spikefrequency curve along with the time evolution process, the onset spikefrequency curve and the steady state spikefrequency curve along with the external electric field changes, and the correlation between successive interspike intervals (ISIs), the effect of external electrical field with different strength or frequency on the adaptability of the proposed model is discussed.